var (
	BinaryCarrier lightstepBinaryCarrier
)

type InMemorySpanRecorder struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

type LightStepStartSpanOption interface {
	ApplyLS(*StartSpanOptions)
}

type Options struct {
	// Recorder receives Spans which have been finished.
	Recorder SpanRecorder
	// DropAllLogs turns log events on all Spans into no-ops.
	// If NewSpanEventListener is set, the callbacks will still fire.
	DropAllLogs bool
	// MaxLogsPerSpan limits the number of Logs in a span (if set to a nonzero
	// value). If a span has more logs than this value, logs are dropped as
	// necessary (and replaced with a log describing how many were dropped).
	//
	// About half of the MaxLogPerSpan logs kept are the oldest logs, and about
	// half are the newest logs.
	//
	// If NewSpanEventListener is set, the callbacks will still fire for all log
	// events. This value is ignored if DropAllLogs is true.
	MaxLogsPerSpan int
}

type RawSpan struct {
	// Those recording the RawSpan should also record the contents of its
	// SpanContext.
	Context SpanContext

	// The SpanID of this SpanContext's first intra-trace reference (i.e.,
	// "parent"), or 0 if there is no parent.
	ParentSpanID uint64

	// The name of the "operation" this span is an instance of. (Called a "span
	// name" in some implementations)
	Operation string

	// We store <start, duration> rather than <start, end> so that only
	// one of the timestamps has global clock uncertainty issues.
	Start    time.Time
	Duration time.Duration

	// Essentially an extension mechanism. Can be used for many purposes,
	// not to be enumerated here.
	Tags opentracing.Tags

	// The span's "microlog".
	Logs []opentracing.LogRecord
}

type Span interface {
	opentracing.Span

	// Operation names the work done by this span instance
	Operation() string

	// Start indicates when the span began
	Start() time.Time
}

type SpanContext struct {
	// A probabilistically unique identifier for a [multi-span] trace.
	TraceID uint64

	// A probabilistically unique identifier for a span.
	SpanID uint64

	// The span's associated baggage.
	Baggage map[string]string // initialized on first use
}

type SpanRecorder interface {
	// Implementations must determine whether and where to store `span`.
	RecordSpan(span RawSpan)
}

type StartSpanOptions struct {
	Options opentracing.StartSpanOptions

	// Options to explicitly set span_id, trace_id,
	// parent_span_id, expected to be used when exporting spans
	// from another system into LightStep via opentracing APIs.
	SetSpanID       uint64
	SetParentSpanID uint64
	SetTraceID      uint64
}

type Tracer interface {
	opentracing.Tracer

	// Options gets the Options used in New() or NewWithOptions().
	Options() Options
}